The practice of medicine is an information-intensive enterprise. A significant portion of a doctor-patient interaction comprises the collection of historical patient information critical to the successful diagnosis and management of disease. A common and long-standing problem relates to the movement of patients between different health care providers within affiliated medical entities and between unaffiliated medical entities, such movement typically stranding the patient's historical medical information at the source institution.
Historically, this problem stems from the paper-based representation of patient medical information, such paper files requiring the burdensome process of copying and mailing to share with others. Laws and regulations relating to patient privacy and information security compounded the difficulty of paper file sharing. However, even as healthcare providers move to adopt digital representations and management of medical information, significant barriers remain to the sharing and transmission of patient information between providers.
Existing medical information management systems are typically categorized by the types of information they handle. For example: picture archiving and communication systems (PACS) handle the storage and retrieval of digital images, radiology information systems (RIS) handle patient demographics, exam scheduling, and storage and retrieval of radiology reports, laboratory information system (LIS) are responsible for the storage and retrieval of lab results, hospital information systems (HIS) handle patient demographics, payer information, scheduling and coordination of care across the hospital, computerized patient order entry (CPOE) systems take instructions from physicians as to patient care and distribute tasks to other caregivers, and electronic medical record (EMR) systems handle the digital acquisition and retrieval of the complete patient record often relying upon a storage system termed a clinical data repository (CDR).
A topic of great importance to the medical community is the means by which these existing systems can be integrated within and across given healthcare enterprises. In some instances, Internet web technologies have been applied to provide standard user interfaces by which patient information is shared between affiliated medical institutions through local area networks (LANs) or wide area networks (WANs). One major initiative sponsored by the Radiological Society of North America (RSNA) and the Healthcare Information Management and Systems Society (HIMSS), entitled “Integrating the Healthcare Environment” or IHE, is developing “plug-and-play” interoperable components that manage patient care and workflow within a single health care system. See Siegel, E. L. & Channin, D. S. 2001 Integrating the Healthcare Enterprise: a primer. Part 1. Introduction. Radiographics 21, 1339–41, Channin, D. S. 2001a Integrating the Healthcare Enterprise: a primer. Part 2. Seven brides for seven brothers: the IHE integration profiles. Radiographics 21, 1343–50, Channin, D. S., Parisot, C., Wanchoo, V., Leontiev, A. & Siegel, E. L. 2001a Integrating the Healthcare Enterprise: a primer: Part 3. What does IHE do for ME? Radiographics 21, 1351–8, Henderson, M., Behlen, F. M., Parisot, C., Siegel, E. L. & Channin, D. S. 2001 Integrating the healthcare enterprise: a primer. Part 4. The role of existing standards in IHE. Radiographics 21, 1597–603 and Channin, D. S., Siegel, E. L., Carr, C. & Sensmeier, J. 2001b Integrating the healthcare enterprise: a primer. Part 5. The future of IHE. Radiographics 21, 1605–8.
However, to the best of applicants' knowledge, there exist no platforms that support integration and digital information sharing at the cross-institutional level, particularly between unaffiliated medical institutions. This failing stems from several critical outstanding obstacles.
In large part, medical data remains largely analog in nature, that is, paper- and film-based. When patient information is contained in digital form, the formats are typically without accepted or implemented standard representations. Some communications standards, however, do exist. HL7 is a standard for electronic data interchange in healthcare environments. Originally developed in 1987 by a group of large healthcare providers who met at the University of Pennsylvania, the standard at first emphasized point-to-point trans-mission of patient-oriented admission/discharge/transfer (ADT), order, and results information in inpatient environments. Today, HL7 prescribes formats for the interchange of information concerning all aspects of the healthcare enterprise, including billing, clinical pathways, care guidelines, referrals, and information about practitioners.
One general area of medical practice overcoming the above-described obstacles to standardized digital data sharing is that of radiology, or diagnostic imaging, where a great deal of patient information is either inherently digital (e.g. magnetic resonance imaging, computed tomography, positron emission tomography, etc.) or acquired digitally (computed radiography, digital radiography). Over the last ten years, hospitals have not only adopted digital radiological systems in large quantity, but are also implementing PACS for storing, interpreting and distributing images in their original digital form. The field of radiology is also a leader with respect to digital data standards, having created and adopted the Digital Imaging and Communication in Medicine or DICOM standard, which is universally accepted and implemented around the world. See 2001 Digital Imaging and Communication in Medicine (DICOM). NEMA Publications PS 3.1–PS 3.12. Rosslyn, Va.: The National Electrical Manufacturers Association (see http://medical.nema.org).
The successes of modern diagnostic imaging have resulted in limited solutions to cross-institutional communication challenges. These solutions, however, are generally restricted to the sharing of digital data between affiliated entities such as hospitals and clinics within a single health system. One early effort begun in 1991 by Martinez and colleagues at the University of Arizona was the “Global PACS” project (Martinez 1996) which sought to use a non-DICOM standard (the Open Software Foundation's DCE and CORBA services) to create an Internet Protocol (IP)-network based, distributed custom system that could exist in multiple geographical locations and enable the sharing of data to facilitate remote diagnosis and consultation between physicians in different locations. In operation, Global PACS included the ability to telecommunicate with voice in synchronization with the review of radiological images. The system could operate over the network or other IP protocol network(s). See, for example, Part II, Martinez, R. 1996 Distributed System Software Via NSFNET for Global Picture Archiving and Communications Systems (Global PACS); NSF Project NCR-9106155 (1991–1995): University of Arizona.
The Global PACS pilot project, which ended about 1996, was successful in linking rural healthcare providers to radiology specialists in an urban center. However, it constitutes a proprietary system that cannot operate with commercial PACS or other “off-the-shelf” components now in widespread hospital use. Further, it does not support ad hoc searches for existing patient data. Nor does it support any method of identifying patients or obtaining patient authorization as would be necessary to transfer data between unaffiliated medical institutions.
In further recognition of the potential for the Internet to connect geographically dispersed healthcare providers, Pinksy and colleagues disclosed three methods and apparatuses that, collectively, created a “radiology healthcare network” capable of sharing radiological information across multiple entities. Their disclosure describes a system by which digital diagnostic imaging information could be routed to radiologists around the world for interpretation, with the resulting radiology reports returned to the source institution. See U.S. Pat. Nos. 5,513,101, 5,655,084 and 5,469,353, all to Pinsky et al.
Although the Pinsky et al. system represented an advance for matching the supply and demand of medical images and interpreters, their system is inherently a “push” system that sends data to specified recipients. The system does not permit an arbitrary user (e.g. an authorized physician) to search the network for a user-specified patient and view or transfer images or reports relating to that patient. In addition they provide no means of securing information as it moves between entities. Nor do they provide for patient identification and authorization to support data sharing between unaffiliated institutions.
Another limitation of Pinsky et al. is a system architecture requiring images to move through a central “administrative” site, thereby creating a bottleneck for information as the number of participating institutions accessing large data sets rises. Further, the invention is applicable only to images and waveforms that require interpretation of some sort and would benefit from such a distribution system for sharing workflow.
A similar proposal, burdened with generally the same deficiencies in terms of scalability and cross-institutional applicability as Pinsky et al., was published by Wilson and colleagues, Wilson et al., in 1995, and termed “virtual PACS.” Like the invention of Pinsky et al., the proposed system was for sharing radiology-specific workflow. Wilson et al. further included a proposed “single patient folder” for organizing content on multiple servers relating to a single patient. Wilson et al. also introduced the notion of pre-fetching across multiple sites, enabling the retrieval from other servers on the network of a patient's historical studies for use by an interpreting radiologist. See Wilson, D. L., Prior, F. W. & Glicksman, R. A. 1995 Virtual PACS, open systems, and the National Information Infrastructure. Proc SPIE 2435, 553–563.
This same group of collaborators later extended the “virtual PACS” concept to a system called a “multiple facility PACS”. The multiple facility PACS proposed the inclusion of “pull” features, that is, the ability of users to search for patient imaging data across multiple servers, and to visualize the results or transfer the data to another destination. Their proposal discloses the use of web technology through the use of an Internet web browser as a universal interface, and they discuss the need for centralized coordination between multiple image servers. See Wilson, D. L., Glicksman, R. A., Prior, F. W., Siu, K.-Y. S. & Goldburgh, M. M. 1996 Filmless PACS in a multiple facility environment. Proc SPIE 2711, 500–509.
Again, this later Wilson et al. system is limited to sharing medical information, specifically radiological, DICOM-based information, between affiliated institutions sharing a common network, common security procedures, and common patient identification system. As the system was proposed, it would not be applicable to multiple, unaffiliated institutions because it did not support necessary patient authorization of data transfer, or authentication methods between entities with no prior relationship. In addition, the latter-proposed Wilson system has problems with scalability due to reliance upon a single web server creating a data bottleneck and total reliance upon DICOM which cannot support more than a few simultaneous associations. Finally, the latter Wilson et al. system does not address other relevant forms of medical information, notably radiology reports which are not typically accessible through DICOM communications.
One recent proposal in the area of management of distributed digital medical information, and one that partially addresses the problem of cross-institutional communication between unaffiliated entities, is the “PACSter” system proposed in an editorial by Channin. See Channin, D. S., Opinion: Is it Time for ‘PACSter’?, Journal of Digital Imaging, Vol. 14, No. 2 (June), 2001: pp 52–53. Channin proposes that PACS-enabled institutions could share imaging data in a purely, or “true,” peer-to-peer fashion. The name for this system could be misinterpreted in that the Channin system is a pure peer-to-peer approach, lacking central coordination, and similar to that approach taken by systems such as Gnutella, BearShare, et. al. This is in contrast to the centrally-mediated, peer-to-peer approach of the namesake Napster system. To the best of applicants' knowledge, the Channin system was never actually built.
The PACSter proposal addresses several of the problems with earlier inventions in this area, including its general extensibility to any form of medical information, the direct transfer of medical data between “peers” avoiding bottlenecks at a central location, and a very limited suggestion for using patient attributes to identify, in the absence of a unique identifier, the same patient between two institutions. It is noted that Channin does not propose an actual solution, but merely suggests that it should be possible to use multiple pieces of patient information to match patients.
While this Channin proposal represents a proposal for cross-institutional, peer-to-peer sharing of imaging data between unaffiliated institutions, Applicants believe that its pure peer-to-peer architecture is not workable in a practical implementation for reasons including lack of scalability, lack of reliability, lack of security, an inability to apply the system to generalized situations, and an absence of patient authorization mechanism for data transfer. With respect to scalability, true peer-to-peer networks such as Gnutella require that queries for data be sent to all known participants. These queries are then propagated to participants known to those participants, and so forth. As such there is no guarantee that all entities are connected and it is possible if not likely some requests may never reach a destination entity actually having the sought after data. Further with respect to scalability, the system proposed by Channin includes large latencies due to multiple propagation steps. It is quite difficult for any one peer to know about and/or organize the contents of all the other peers on the network. Further, DICOM and HL7 are insufficient to support peer-to-peer transfer due to their static configuration of IP addresses, i.e. each hospital would need to be hard-wired to accept communications from every other hospital. DICOM supports only a limited number of simultaneous connections, and HL7 does not support queries of any kind.
With respect to the reliability of the Channin-proposed system, reliability and integrity in a peer-to-peer network are dependent on which hospitals are up and running appropriate software at any given point in time. Hospital information systems and PACS in particular are notorious for unreliability, with uptime in the range of about 97% (as compared, for example, to financial systems that may approach 99.999% uptime). This typical unreliability corresponds to nearly 11 full days (or 263 hours of downtime per year). In a true peer-to-peer network, if a peer is down, a request for data will be unanswered even if the desired data exists on that peer.
With respect to the security of the Channin system, there exists no trusted authority known to the applicants with which to establish trusted communication links between medical institutions. Hospitals are typically unaffiliated outside of their immediate group, and there are strong economic and political barriers to trusting one-another. To the best of applicant's knowledge, no 3rd party currently exists that can create dynamic associations on-the-fly between two hospitals or a physician and a hospital that have no prior affiliation. Such associations would be difficult if not impossible with a true peer-to-peer network. Moreover, true peer-to-peer networks suffer from potential security exploits in the form of malicious users masquerading as peers. With respect to generalized situations, the PACSter concept is limited to PACS-enabled institutions and fails to address access to and sharing of information by those entities that do not possess such technology.
Finally, Channin does not contemplate a solution to the problem of patients authorizing the transfer of digital data between unaffiliated institutions, a cornerstone of international data privacy regulations including HIPAA in the United States and the Directives of the European Council.
While there have been various disclosures and proposal for methods to connect parties for the purpose of sharing digital medical information, significant obstacles remain to communication between parties not possessing an a priori relationship. Notably lacking are means of identifying data relating to the same patient at different institutions given the absence of unique patient identifiers of national and international scope, and means for efficiently obtaining an authorization from the patient permitting the transfer of his or her data. Moreover, these earlier proposals all suffer from significant drawbacks in scalability of participants in a network be they users or, more importantly, medical institutions providing the data, in security of communications and data transfers, in compliance with data privacy regulations, and in reliability in uptime and hence finding all relevant data. In addition, these earlier proposals do not provide a means of accessing data from information systems that do not support query/retrieve operations (e.g. systems containing only an HL7 interface) nor do they afford users at institutions lacking digital imaging capabilities a means of participating in the network.
As a result of these obstacles and despite the tremendous potential benefit to patients afforded by secure, portable digital information, present-day communication of historical patient data between healthcare providers generally remains limited to the physical transfer of data on paper or film (by hand or conventional mail), or by facsimile transmission of paper records over telephone networks. In every instance the appropriate paper-based authorization of such transfer(s) is authorized by the patient.
There thus exists a need for new and improved methods and systems for managing digital health care information, which solves the problems of the prior art.